Torque clutch mechanism in an air wrench

ABSTRACT

A torque clutch mechanism in an air wrench, comprising a torque clutch means capable of not only closing an air supply suspension valve by detecting an excess counterreactive force when such force is applied to the rotor shaft of said air wrench, but also reversing said rotor shaft.

United States Patent [1 1 Nakai TORQUE CLUTCH MECHANISM IN AN AIR WRENCH[76] Inventor: Sinii Nakai, No. 799 Kurotani, Yao,

Osaka Prefecture, Japan 22 Filed: 0ct.26,1971

21 App1.No.: 192,228

[30] Foreign Application Priority Data Mar. 13, 1971 Japan 46/16741 Mar.13, 1971 Japan 46/16742 Mar. 13, 1971 Japan 46/16743 Mar. 13, 1971 Japan46/16744 OCt. 27,1970 Japan 45/94951 [52] US. Cl 192/56 R, 173/12,192/.O34,

192/44, 192/45 [51], Int, Cl. Fl6d 41/07, F16d 71/00, E210 5/16 [58]Field of Search 192/44, 45, 56 R [56] References Cited UNITED STATESPATENTS 2,889,022 6/1959 Better at a]. 192/56 R Aug. 14, 1973 2,391,35012/1945 Schmidt 192/45 2,683,362 7/1954 Bowman 192/56 R X 2,989,1606/1961 Woodruff 192/44 X 3,305,057 2/1967 McAlpin et a1 192/44 X FOREIGNPATENTS OR APPLICATIONS 594,141 3/1934 Germany ..192/45 278,427 10/1927GreatBritain ..192/45 Primary Examiner- Allan D. Herrmann Attorney- E.F. Wenderoth, V. M. Creedon et a1.

[ 5 7] ABSTRACT A torque clutch mechanism in an air wrench, comprising atorque clutch means capable of not only closing an air supply suspensionvalve by detecting an excess counterreactive force when such force isapplied to the rotor shaft of said air wrench, but also reversing saidrotor shaft.

4 Claims, 29 Drawing Figures Patented Aug. 14, 1973 6 Sheets-Sheet 1FIG.|A FIG. IB F|G.|C

Patented Aug. 14; 1973 3,752,277

6 Sheets-Sheet 2 o y g 26 FIG. 6A FIG. 68 FIG. 6C

Patented Aug. 14, 1973 3,752,277

6 Sheets-Sheet 5 FIG.7A FIG.7B F|G.7C

I 43 41 4a 43 A 44 44 44 2s 2s 2s Patented Aug. 14, 1973 6 Sheets-Sheet4.

FIG.|OA FIG.|OB F|G.IOC

Patented Aug. 14, 1973 3,752,277

6 Sheets-Sheet 5 HEJ? FIG. I3A FIG. I38 FIG. BC

Patented Aug. 14,1973 3,752,277

6 Sheets-Sheet 6 FIG. |7A FIG. I7B FIG- 77c 7a A H /n 7B TORQUE CLUTCHMECHANISM IN AN AIR WRENCH This invention relates to torque clutchmechanism in an air wrench, and more particularly to a torque clutchadapted to clutch the rotary shaft up to a predetermined small torquebut to cause said rotary shaft to idle if said torque is exceeded whenthe direction of the rotation of the rotary shaft is altered.

Heretofore, torque clutches of this type have been of the constructionas described in the specification of U.S. Pat. No. 3,305,057. Ascompared with those prior arts, the torque clutch mechanism according tothis invention comprises a plurality of rotary rolls which are supportedby spring means provided on the internal periphery of the clutchmember,'said rotary rolls being brought into contact with the externalperiphery of the rotary shaft between the clutch member and said rotaryshaft positioned thereinside, said rotary rolls simply rotatingsupported by the spring means during the rotation of the rotary shaft,said rolls however being held up between the clutch member and therotary shaft when the direction of the rotation is altered, therebyclutching both members, said rotary rolls being displaced when torqueexceeding the predetermined small torque is applied, thereby causing therotary shaft to idle. This invention therefore concerns a torque clutchmechanism applicable to an air wrench based upon the torque clutch asdescribed hereinbefore.

This invention has for its object to provide a very convenientlyoperatable air wrench wherein, when excess counterforce is applied tothe rotor shaft of the air wrench, the clutch member is adapted to beclutched to a detector shaft integrally formed with the rotor shaft,thereby rotating within the scope of a predetermined angle an operationlever provided on the clutch member, a lever activating an air supplysuspension valve being operated during said reverse, thus enabling therotor shaft to rotate reversely urged by a counterforce greater than thepredetermined torque acting upon the clutch in the state of saidrotation within the scope of the predetermined angle, as a result ofwhich the excess counterforce detector member is not only free from therisk of burning but capable of suspending the air supply in response toan excess counterforce, moreover the original state being restorable bythe release of a throttle lever.

These and other objects are accomplished by the parts, improvements,combinations and arrangements comprising the invention, preferredembodiments of which are shown by way of example in the accompanyingdrawings, and herein described in detail.

Various modifications and changes in details of construction arecomprehended within the scope of the appended claims.

This invention concerns an air wrench to which is applied a torqueclutch mechanism wherein, between a clutch member and a rotary shaftpositioned thereinside, a plurality of movable rolls supported by springmembers provided on the internal periphery of the clutch member arebrought into contact with the external periphery of the rotary shaft,the movable rolls simply rotating supported by the spring members duringthe rotation of the rotary shaft, however in the case of reverserotation said rolls being held up between the clutch member and therotary shaft thereby clutching both members, the movable rolls beingdisplaced when torque greater than the predetermined value is applied,thereby allowing the movable rolls to idle.

In the figures:

FIGS. lA-lC show sectional views of the torque clutch applicable to theair wrench of this invention.

FIG.2 is a descriptive figure of the spring member shown in FIG.1.

FIG.3 is a sectional view showing a modification of FlG.1.

FIG.4 shows a lateral view of an air wrench to which is applied thetorque clutch as designated in FIG.1, of which a part is omitted andbroken away.

FIG.5 is a sectional view taken on the line V-V in FIG.4.

FIGS. 6A-6C are descriptive figures showing an embodiment of the torqueclutch for excess counterforce detection.

FIGS. 7A-7C are descriptive figures showing the clutching action at thetime of excessive counterforce detection.

FIG.8 is a sectional view showing another embodiment of the torqueclutch, of which a part is omitted.

FIG.9 is a lateral view of the torque clutch shown in FIGS, of which apart is omitted.

FIGS. l0A-l0C are descriptive figures showing the clutching action atthe time of shift of rotation of the torque clutch shown in FIGS.

FlG.ll is a sectional view showing still another embodiment of thetorque clutch, of which a part is omitted.

F IG.12 is a lateral view of the torque clutch shown in FlG.ll, of whicha part is omitted.

FIGS. 13A-13C are descriptive figures showing the clutching action atthe time of shift of rotation of the torque clutch designated in FlG.ll.

FlG.l4 is a sectional view showing still another embodiment of thetorque clutch, of which a part is omitted.

FlG.lS is an elevation showing the clutch member in FIG.14.

FlG.l6 is a sectional view taken on the line XVI- --XVI in FlG.l4.

FIGS. 17A-l7C are descriptive figures showing the clutching action atthe time of shift of rotation of the torque clutch designated in FlG.l4.

The fundamental construction of the torque clutch in the air wrenchaccording to the invention is as shown in FIGS.1 to 3, in which thenumeral 1 designates a clutch member, 2 designating a rotary shaft,clutching action being effected between these two members within thepredetermined torque at the time of shift of rotation of the rotaryshaft 2. As shown in FIG.1, grooves 3 are provided in several locations(at least more than three locations) on the internal surface of theclutch member 1, spring members 4 being fitted into said groooves 3,each of said spring members 4 being formed into a stationary rollreceiving section 5, a movable roll 9 being interposed between thestationary roll 8 and the rotary shaft 2, said roll 9 being preventedfrom dislocation by means of the pressure element 6, the spring member 4being prevented from rotating relative to the clutch member 1 by meansof the rotation prevention section 7. Now, the movable rolls 9 have adiameter D which is H+'y('y=maximum-1'ninimum), H representing theshortest distance between the external periphery of the rotary shaft 2and that of the stationary roll 8, so that the movable rolls will notpass freely between said shortest distance H. Accordingly, in order thatthe rotary shaft 2 may alter the direction of its rotation relative tothe clutch member, for instance from A to B, C or from C to B,A in F161,it is necessary that torque which is greater than the predeterminedsmall torque should be applied.

To be more precise, in the state of idling in the clockwise direction ofrotation (a) in FlG.1, A. The movable roll 9 is free though pressed bythe pressure element 6 owing to the rotation of the rotary shaft 2.However, in case the rotation is altered into counterclockwise rotation(b), if the torque forcing the rotary shaft 2 to rotate in saiddirection (b) is small, the rotary shaft 2 is clutched to the clutchmember 1 by the friction between said rotary shaft 2, movable rolls 9and stationary rolls 8, and the additional force of the pressure element6 of the spring members 4.

Then, according as the torque of counterclockwise rotation (b) of therotary shaft 2 increases, the movable rolls 9 are compressed or therotary shaft 2 and the stationary rolls 8 are separated from each other,thus the diameter D of the movable rolls 9 becoming the same as or lessthan the clearance H, as a result of which said movable rolls 9 are setfree by shifting to the positions of FIG. IC through the positions ofFIG. 1B, thus the rotary shaft 2 idles in counterclockwise rotation (b)relative to the clutch member 1. This is also the case with the rotaryconversion from counterclockwise rotation (17) to clockwise rotation(a).

FIG.3 shows that a spring member 10 integrally secured to the inside ofthe clutch member 1 is provided as a substitute for the spring members 4in FIG. 1, movable roli receiving sections 11 being provided at thefront end thereof, movable rolls 9 being fitted into the receivingsections 11.

Each movable roll 9' is constantly brought into contact with theexternal periphery of the rotary shaft 2, the spring member 10constantly urging the roll 9' toward the axis, said movable roll 9 alsoperforming the same action as the aforementioned roll 9 does, with theresult that, for the rotary shaft 2 to alter its rotationcounterclockwise from its clockwise (a) idling, it is necessary that therotary shaft 2 should be once clutched and then torque that is greaterthan the predetermined small torque should be applied thereto. This isalso the case with the reverse thereof.

As described hereinbefore, the clutch shown in FIGSJ to 3, in the caseof rotary conversion, clutches the rotary shaft 2 to the clutch member 1within the predetermined small torque. Then, if the clutch member l issecured, the rotary torque in the rotary shaft 2 is infinite, andtherefore said small torque applied to the clutch member I at the timeof rotary conversion of the rotary shaft 2 is momentary. However, if theclutch member 1 is adapted to be rotatable within the scope of apredetermined angle, only a small torque sufficient to rotate the clutchmember 1 within said scope is applied at the time of rotary conversion,the clutch member 1 being thus arrested after rotating through thepredetermined angle, resulting in that the rotary shaft 2 idles asdescribed hereinbefore.

Consequently, if the clutch is so provided that, for instance, it allowsthe clutch member to rotate within the scope of a predetermined angle,in the case of rotary conversion of the rotary shaft under influence ofa counterforce applied thereto, said rotary shaft and clutch member aretemporarily clutched, however the clutch member being capable ofrotating within the scope of a predetermined angle, and thereforedetection of the rotation within said scope enables one to detect therotary conversion of the rotary shaft. Since the driving source of therotary shaft can be cut off by the detection signal, said rotary shaftand the like are protected from damage. Moreover, the scope ofapplication is very extensive because this device is applicable to bothclockwise and counterclockwise rotation.

As described hereinbefore, this invention provides a torque clutchmechanism in an air wrench as shown in FIGS.4 and 5 by the applicationof a torque clutch as illustrated in FIGS.1 to 3.

Referring to FIGS.4 to 7, the numeral 21 designates an air wrenchmember, a rotor 23 being rotated by supplying air by the operation of athrottle lever 22, thereby rotating an anvil 24 positioned at the frontend of the wrench member 21. At the rear end of the rotary shaft 25 ofthe rotor 23 is integrally formed an excess counterforce detector shaft26, a torque clutch mechanism 27 having a clutch member 27 built in onthe external periphery of the detector shaft 26 centering thereon, theclutch member 27 being so adapted as to be capable of rotating withinthe scope of angle 0 by providing an operation lever 28 on said clutchmember 27. The numeral 29 designates an air supply suspension valvemember, said member 29 being capable of intercepting the supply of airwhich is fed to a chamber 20 by the operation of the throttle lever 22before said air reaches the chamber of the rotor 23 interposed between avalve and a valvemember 29 facing the chamber 30. in the ordinary stateas shown in FIG.4, air reaches an inner chamber 35 from the chamber 30through a hole 34 provided in the valve 31, said air further being fedto the chamber of the rotor 23 by way of a passage 31 through a hole 36provided in the valve member 29.

A lever arrester member 38 for arresting a lever 39 is formed at thefront end of the valve shaft 32, said member 38 being capable ofpreventing the valve 31 and the valve shaft 32 from being displaced bythe air pressure from the chamber 30. The numeral 40 designates a pinfor controlling said valve 31 so as not to be pushed out more thannecessary by the spring 33 when the air pressure no longer exists in thechamber 30. The numeral 41 designates a pin for determining the normalposition of the operation lever 28, said operation lever 28 beingnormally brought into contact with a wall 42 formed on the wrench member21 by the pressure of said pin 41.

The torque clutch mechanism consisting of the aforementioned clutchmember 27 comprises movable rolls 44 interposed between stationary rolls43 fitted into the internal periphery of the clutch member 27 and thedetector shaft 26, said movable rolls 44 having a slightly greaterdiameter than the smallest clearance between said stationary rolls 43and the detector shaft 26, and spring members 45 constantly urging saidmovable rolls 44 into contact with the stationary rolls 43 and thedetector shaft 26 without allowing said movable rolls 44 to play, sothat, when the detector shaft 26 shifts its rotation under the influenceof a counterforce applied to the rotor shaft 25 through the anvil 24,the clutch member is clutched to the detector shaft 26 through saidmovable rolls 44. Three embodiments of the predetermined torque clutchare shown in FIGS. 6A-6C.

The numeral 46 in FIGS. 6A and 6B designates an auxiliary roll which isinterposed between the detector shaft 26 and the clutch member and alsobetween movable rolls 44, thereby serving to stabilize the clutchingaction. In FIG. 6B the stationary rolls 43 are resilient rollsconsisting of a helical plate spring or the like. Furthermore, in FIGS.6C the spring members 45 consist of twisted coil springs, a pin 47 beingprovided to support each spring, a projection element being formed onwhich to provide said pin 47.

Hereunder is explained the action when excess counterforce is applied tothe anvil 24 of the air wrench. This air wrench 21 conducts anintermittent screwing action by means of the anvil 24, and supposingthat the rotor shaft 25 is rotating clockwise A, a counterforce againstthe rotation of the rotor 23 becomes greater with the progress of thescrewing operation, a force to reverse the rotor shaft 25 increasing asa result. Now, if the rotor shaft 25 is reversed by said counterforce,the clutch performs an action as described hereunder.

In a state wherein the detector shaft 26 rotates clockwise A relative tothe rotor shaft 25, the movable rolls 44 are rolled by the detectorshaft 26 while being supported and forced into contact with thestationary rolls 43 by the spring members 45, the clutch member 27 beingarrested by the counterforce, the operation lever 28 being brought intocontact with the wall 42. How ever, if the rotation of the rotor shaft25 is reversed, the detector shaft is also rotated counterclockwise A,consequently the movable rolls 44 that have been rolling while beingheld between the detector shaft 26 and the stationary rolls 43 as shownin FIG.7, A, the friction arising therefrom resulting in transmittingthe reversal of the detector shaft 26 to the clutch member 27 throughthe stationary rolls 43, thereby causing the clutch member 27 to rotatecounterclockwise A, the operation lever 28 being also rotated as aresult. This rotation however is terminated by the operation lever 28which is brought into contact with the pin 41 after rotating through theangle 0. To be more precise, by the contact of the operation lever 28with the pin 41, the great counterforce acts upon the stationary rolls43 through the member 27, great torque acting upon the stationary rolls43 from the detector shaft 6, consequently friction of the movable rolls44 against the detector shaft 26 and the stationary rolls 43 ismaximized, the mutual compression and deformation resulting in the stateas shown in FIGS. 78. Therefore, the rotor shaft 25 is reversed inresponse to the excess counterforce acting upon the anvil 24,simultaneously the lever 39 being knocked by the operation lever 28 whensaid operation lever 28 has rotated through the angle 0, consequentlythe valve 31 which is disengaged from the arresting section 38 of thevalve shaft 32 being pushed by the air pressure of the chamber 30 inresistance to the spring 33, thus stopping the air supply from thechamber 30 to the chamber of the rotor 23 byblocking the hole 36 withthe external periphery of said valve 31. Then, since the air pressure tothe chamber 30 is removed by releasing the throttle lever 22, the valve31 is restored by the pressure of the spring 33, the operation lever 28is also restored by the pressure of the pin 41, the lever 39 beingengaged with the arresting section 38 of the valve shaft 32, thus theentire mechanism being restored to its original state.

As described hereinbefore, the air wrench of this invention is sodevised that, when excess counterforce is applied to the rotor shaft,the clutch member is clutched to the detector shaft integrally formed onthe rotor shaft, the operation lever provided on the clutch member beingrotated through a predetermined angle, the lever for activating the airsupply suspension valve being operated during the reverse, acounterforce exceeding the predetermined torque acting upon the clutchin the state after the rotation through the predetermined angle, therebyenabling the rotor shaft to reverse.

Therefore, this invention makes it possible to suspend the supply of airduring excess counterforce without the risk of burning the excesscounterforce detector member unlike in the case of the known system.Moreover, since the entire mechanism is restored to its original stateby the operation of the throttle lever, this invention is capable ofsimplifying the handling to a great extent.

The torque clutches illustrated in FIGS.8 to 17 each have embodiments ofa different type wherein, when excess counterforce is applied to therotary shaft of the air wrench or the like, or in the case of rotaryconversion, the rotary shaft is clutched until the torque reaches apredetermined value but said shaft idles when the torque exceeds saidpredetermined value.

Referring to FIGS.8 to 10C, the numeral 51 designates a clutch member,52 designating a rotary shaft connected to the rotary shaft of the airwrench or the like, clutching between said members being effected withinthe scope of a predetermined small torque at the time of the conversionof the rotary shaft 52. Grooves 53 are formed at a plurality oflocations on the internal periphery of the clutch member 51, stationaryrolls 55 being fitted into the grooves 53 with spring members 54interposed therebetween. A main roll 56 for clutching action isinterposed between each of the stationary rolls 55 and the rotary rolls52, the spring members 54 being provided so that the rolls 56 are notallowed to idle but are constantly brought into contact with the rotaryshaft 52 and the stationary rolls55. Now, between the minimum clearanceH from the rotary shaft 52 to each stationary roll 55 (see FIG.10, A)and the diameter D of the main roll 55 there exists a relation of H D,that is, D is slightly larger then H.

Furthermore, auxilliary rolls 57 for operating the clutch are rotatablyinterposed between the clutch member 51 and the rotary shaft 52, moreparticularly between the parts having no rolls 56, that is betweenadjacent rolls 56. The numeral 58 designates an operation lever mountedon the clutch member 1 secured in the direction of rotation, said lever58 being caused to rotate simultaneously with the clutch member 51 so asto perform the predetermined action when the clutch member 51 isclutched to the rotary shaft 52 at the time of conversion thereof (thatis, when excess counterforce is applied in the case of the air wrench).

In the construction as described hereinbefore, the clutching operationis conducted as explained hereunder. Supposing that the rotary shaft 52rotates in the arrow-indicated direction A shown in FIGS, the main rolls56 for the clutching operation are rotated in the arrow-indicateddirection B by the rotary shaft 52, said main rolls 55 being broughtinto contact with the stationary rolls 55 by the spring members, theauxilliary rolls 57 being rotated simultaneously in the arrowindicateddirection B. In the meantime, the clutch member 51 is halted under theinfluence of counterforce C, the operation lever 58 being brought intocontact with the suitable portion of the apparatus forming part of theclutch. And supposing that in the aforementioned state the rotation ofthe rotary shaft 52 is converted by an excess counterforce applied tothe rotary shaft 52 or some other influence, that is, if the rotaryshaft 52 shifts its rotation in the arrow-indicated direction A, theclutch member 51 is temporarily clutched to the rotary shaft 52 withinthe scope of the predetermined torque as explained hereinunder. That is,in the case of rotary conversion from the state as shown in FIG.8, sincethe clutch member 51 (i.e., the operation lever 58) is adapted to befree from counterforce in the direction of A, the clutch operation mainrolls 56 are held up between the rotary shaft 52 and the stationaryrolls 55 as illustrated in FIGJO, A, the friction resulting therefromtransmitting the rotation of the rotary shaft 52 to the clutch member 51through the stationary rolls 55, thereby causing the clutch member 51 torotate in the direction A. The torque needed for the rotation of theclutch member is obtained from the friction of the main rolls 56 againstthe rotary shaft 52 and the stationary rolls 55. And when the clutchmember 51 is rotated through the angle and counterforce C is applied tothe operation lever 58 (i.e., the state wherein the operation lever 58is brought into contact with a stopper provided at a suitable position),the stationary rolls 55 are subjected to the great counterforce C sothat said stationary rolls 55 are forced to transmit said great torque,as a result of which the friction of the main rolls 56 against therotary shaft 52 and the stationary rolls 55 is maximized, therebycausing transition to the state illustrated in FlG.8 (C) through thestate of FIG.8 (B). Since the main rolls 56 are urged by the springmembers 54, said rolls 56 are brought into contact in the reversedirection and rotated in the direction B without being separated fromthe rotary shaft 52 and the stationary rolls 55. At the same time, theauxilliary rolls also rotate in the direction B, though not shown in thedrawing.

As explained hereinbefore, the clutch of this embodiment is a torqueclutch adapted to clutch by small torque which is sufficient to rotatethe clutch member at the time of the rotary conversion of the rotaryshaft, the clutch being released when the clutch member is arrested andgreat torque is applied by the action of great counterforce. Therefore,if the clutch member is adapted to be capable of rotating through apredetermined angle by providing an operation lever on said clutchmember, when the rotary shaft shifts its rotation under the influence ofexcess counterforce, the clutch member is clutched to the rotary shaftand rotated through the predetermined angle. Therefore, the change inrotation of the rotary shaft is detectable by a limit switch or thelike. Consequently, in the case of the air wrench, the air supplyinterception valve thereof is controllable, thereby protecting therotary shaft and the like. Moreover, between the clutch member and therotary shaft auxilliary rolls are interposed between main rolls, andtherefore in the case of displacement of each main roll at the time ofthe clutching operation, said roll is simultaneously displaced guided bythe auxilliary rolls, making it possible to stabilize the clutchingoperation to a-great extent.

in addition thereto, the clutch according to this embodiment, whenapplied to clockwise and counterclockwise rotary machines, makes itpossible to detect the rotary conversion by temporarily clutching therotary shaft at the time of the conversion.

The torque clutch illustrated in F [68.11 to 13C shows still anotherembodiment. Referring to the drawings, the numeral 61 designates aclutch member, 62 designating a rotary shaft connected to a rotor shaftof an air wrench or the like, clutching operation being effected withinthe scope of a predetermined small torque between both said members atthe time of rotary conversion of the rotary shaft 62. On the internalperiphery of the clutch member 61 are formed grooves 63 at a pluralityof locations thereof, resilient rolls 65, such as helical plate springs,being fitted into said grooves through spring members 64. Between theresilient rolls 65 and the rotary shaft 62 clutch operation main rolls66 are interposed, the rolls 66 being urged by the spring members 64 sothat said rolls 66 may be constantly brought into contact with therotary shaft 62 and the resilient rolls 65 without idling. Now betweenthe minimum clearance H from the rotary shaft 62 to the resilient rolls65 (see FIG.13, A) and the diameter D of the main rolls 66, there existsa relation of H D, that is, D is slightly greater than H. Between theclutch member and the rotary shaft 62 clutch operation auxilliary rolls67 are rotatably interposed at the places having no rolls 66, i.e.,between the rolls 66. The numeral 68 designates an operation levermounted on the clutch member 61 with a fixed rotary direction, saidlever 68 being rotated simultaneously with the clutch member 61 forconducting the predetermined action at the time of the rotary conversionof the rotary shaft 62 (i.e., when excess counterforce is applied in thecase of an air wrench).

Hereunder is explained the clutching action in the aforementionedconstruction. Supposing that the rotary shaft 62 is rotating in thedirection A shown in F 16.11, the clutch operation main rolls 66 arerotated by the rotary shaft 62 in the arrow-indicated direction B whilebeing urged by the springs 64 and brought into contact with the surfaceof the resilient rolls 65, simultaneously the auxiliary rolls 67 beinglikewise rotated in the arrow-indicated direction B. At this instant,the clutch member 61 is halted by counterforce C, the operation lever 68being brought into contact with a suit able part of the apparatus onwhich the clutch is provided. And supposing that the rotary shaft 62shifts its rotation owing to the action of a counterforce or the like,that is, the rotary shaft 62 shifts its rotation to the arrow-indicateddirection A, the clutch member 1 is' temporarily clutched to said rotaryshaft 62 within the scope of a predetermined torque in a manner asdescribed hereunder. That is, in case the conversion is effected fromthe state of rotation in the direction A in FIGJI, since the clutchmember 61 (namely, the operation lever 68) is so adapted as to be freefrom counterforce in the direction A, the clutch operation main rolls 66are held between the rotary shaft 62 and the resilient rolls 65 asillustrated in 1 16.13, A, by the friction resulting therefrom therotation of the rotary shaft 62 being transmitted to the clutch member61 through the resilient rolls 65, thereby rotating the clutch member 61in the direction A. The torque needed for the rotation of the clutchmember 61 is obtained from the friction of the main rolls 66 against therotary shaft 62 and the resilient rolls 65, and the torque is not sogreat that it will compress the resilient rolls 65. And when the clutchmember 61 is rotated through the angle 0 and the operation lever 68 issubjected to counterforce C (i.e., in the state wherein the operationlever 68 is brought into contact with a stopper provided at a suitableposition), the great counterforce C acts upon the resilient rolls 65,thereby bringing the clutch member to a halt, great torque acting uponthe resilient rolls 65 from the rotary shaft 62, thus the friction ofthe main rolls 66 against the rotary shaft 62 and the resilient rolls 65being maximized, thereby compressing and distorting the resilient rolls65, resulting in transition from the state of FIG.13 (B) to the state ofFIG.13 (C). In the meantime, since the main rolls 66 are urged by thespring member 64, said rolls 66 are reversely compressed withoutseparating from the rotary shaft 62 and the resilient rolls 65, therebyeffecting rotation in the direction B. Simultaneously, the auxilliaryrolls 67 also rotate in the direction B, though not shown in thedrawings.

As explained hereinbefore, the clutch of this embodiment is apredetermined torque clutch in which clutching is effected by a smalltorque that is sufficient to rotate the clutch member at the time of therotary conversion of the rotary shaft, great torque resulting from theaction of great counterforce arising from stoppage of the clutch member,with the result that the clutched state is released, thereby allowingthe rotary shaft to idle. Consequently, if the clutch member is adaptedto be rotatable through a predetermined angle by providing an operationlever or the like on said clutch member, said clutch member clutched tothe rotary shaft rotates through the predetermined angle when therotation of the rotary shaft is converted by excess counterforce appliedthereto, and therefore the rotary conversion is detectable by a limitswitch or the like. In the case of air wrenches, the air supplysuspension valve is controllable, thereby protecting the rotor shaft andthe like from damage.

Furthermore, stabilized clutching action is obtainable through themutual intervention between the main rolls by interposing auxilliaryrolls therebetween, and moreover resilience of the stationary rollsfitted into the clutch member makes it possible to obtain the effects asstated hereunder. That is, for instance, said resilience and the factthat the diameter D of the main rolls is appropriately modified inrelation to theclearance H makes it possible to set the maximum value ofthe predetermined torque freely and furthermore its compresseddistortion makes it possible to ensure the clutching action with greaterprecision. In addition thereto, repetition of the compressed distortionis practicable for a long period of time, thereby ensuring a long lifeof the apparatus. Needless to mention, the clutch of this embodiment,when applied to the rotary shaft of clockwise and counterclockwiserotary apparatus, makes it possible to detect the rotary conversion bytemporarily clutching the shaft at the time of the conversion.

The torque clutch illustrated in FIGS.14 to 17C shows still anotherembodiment.

Referring to the drawings, the numeral 71 designates a clutch member, 72designating a rotary shaft connected to a rotor shaft of an air wrenchor the like, clutching action being effected between these two memberswithin the scope of predetermined small torque at the time of rotaryconversion of said rotary shaft 72. On the internal periphery of theclutch member 71 are provided a plurality of projection elements 74 thatform grooves 73 for fitting a plurality of stationary rolls thereinto,said projection elements 74 being adapted to support pins 75, twistedcoil springs 76,77 being fitted to said pins 75.

Between each stationary roll 78 fitted into the groove 73 and theexternal periphery of the rotary shaft 72 is interposed a movable roll79, said roll 79 being urged by legs depending from the coils of thesprings 76,77 so as to be constantly brought into contact with therotary shaft 72 and the stationary roll without idling. Furthermore,between the minimum clearance H from the rotary shaft 72 and thestationary roll 78 (see FIG. 17(A)) and the diameter D of the movableroll 79, there exists the relation of H D, i.e., D being slightlygreater than H. The movable roll 79 is brought into contact with thelateral parts of the projection element 74 that form the groove 73 sothat, at the time of conversion of the rotary shaft 72 which isdescribed hereinafter, said movable roll 79 will not be roteted morethan necessary and separated from the stationary roll 78. The numeral 81designates an operation lever mounted on the clutch member in thedirection of its rotation, said lever- 81 being rotated simultaneouslywith the clutch member 71 to perform the predetermined action, when saidclutch member 71 is clutched to the rotary shaft 72 at the time of therotary conversion thereof (when excess counterforce is applied in thecase of an air wrench).

In the aforementioned construction, the clutching action is explainedhereunder. That is, supposing that the rotary shaft 72 is rotating inthe direction A shown in FIG. 1, the movable rolls 79 rotate in thearrowindicated direction B while being urged by the springs 76 andbrought into contact with the stationary rolls 78. At this instant, theclutch member 71 is brought to a halt by a counterforce resulting fromcontact of the operation lever 81 with a suitable part of the apparatusprovided with this clutch. And supposing that the rotary shaft 72 issubjected to excess counterforce or the like and shifts its rotation,that is, the rotation of the rotary shaft 72 is converted to thearrow-indicated direction A, the clutch member 71 is temporarilyclutched to the rotary shaft 72 within the scope of a predeterminedtorque in a manner as described hereunder. That is, in the case ofconversion from the rotation in the direction A shown in FIG.14, sincethe clutch member 71 (i.e., the operation lever 81) is so adapted as tobe free from counterforce in the direction A, the rotary rolls 79 areheld between the rotary shaft 72 and the stationary roll 28 asillustrated in FIG. 17, A, the rotation of the rotary shaft 72 beingtransmitted by the friction to the clutch member 71 through thestationary rolls 78, thereby rotating the clutch member 71 in thedirection A. The torque needed for the rotation of the clutch member 71is easily obtainable from the friction of the movable rolls 79 againstthe rotary shaft 72 and the stationary rolls 78. The clutch member 71 isrotated through the angle 6, thus counterforce C acting upon theoperation lever 81 (i.e., the state wherein the operation lever 81 isbrought into contact with a stopper provided at a suitable place), as aresult of which the clutch member 71 is brought to a halt by the greatcounterforce C acting upon the stationary rolls 78, the friction of themovable rolls against the rotary shaft 72 and stationary rolls 78 beingconsequently maximized, thus transition to the state shown in FIG.17 (C)from that shown in FIG.17 (B) being realized. In the meantime, since themovable rolls are supported by the springs 77 and brought into contactwith the lateral part 80 of the projection element 74, said movablerolls are brought into contact with reverse side by said springs 77without being separated from the rotary shaft 72 and the stationaryrolls 78, thus said movable rolls being rotated in the direction B inaccordance with the rotation of the rotary shaft 72 in the direction A.

As explained hereinbefore, the clutch of this embodiment is apredetermined torque clutch wherein clutching is effected by a smalltorque that is sufficient to rotate the clutch member at the time ofrotary converson of the rotary shaft, so that the clutch is released toallow the rotary shaft to idle when the clutch member is arrested andgreat counterforce arises. Consequently, if the clutch member is capableof rotating through a predetermined angle by providing an operationlever or the like on said clutch member, said clutch member rotatesthrough said predetermined angle clutched by the rotary shaft when therotation of the rotary shaft is converted by excess counterforce actingthereupon, thereby making it possible to detect the rotary conversion ofthe rotary shaft making use of a limit switch or the like. In the caseof the air wrench, the air supply suspension valve is controllable,thereby making it possible to protect the rotor shaft and the like.Moreover, since a twisted coil spring is employed to support the movableroll so that it does not idle, the action of the spring upon the movableroll is ensured. Moreover, the spring is not only fit for repeated usefor a long period of time but also capbale of being formed in a greatersize. In addition thereto, since the movable roll is adapted to bebrought into contact with and supported by the lateral part of theprojection element that forms a groove for receiving the stationaryroll, the movable roll is free from the risk of being rotated more thannecessary at the time of rotary conversion, thereby making it possibleto stabilize the clutching action. It goes without saying that theclutch of this embodiment, when applied to the rotary shaft of aclockwise and counterclockwise rotary apparatus, makes it possible todetect the conversion by means of temporarily clutching at the time ofthe conversion.

As stated hereinbefore, this invention concerns an air wrench to which atorque clutch is applied, it being adapted to prevent an excesscounterforce detector member from the risk of burning, and making itpossible to suspend the air supply at the time of excess counterforce,and moreover making it possible to restore the entire mechanism to itsoriginal state by the releasing operation of the throttle lever. Inaddition to the aforementioned advantages, the air wrench of thisinvention excels in that it is extremely easy to handle.

I claim:

1. A torque clutch for an air wrench, comprising an annular clutchmember, a rotary shaft positioned within said annular clutch member witha space between the annular shaft and the clutch member, a plurality ofstationary rolls mounted at intervals around the internal periphery ofsaid annular clutch member, a plurality of spring members mounted aroundthe internal periphery of said annular clutch member at positionsadjacent said stationary rolls, a plurality of main movable rolls equalin number to the number of stationary rolls and having a diameterslightly larger than the clearance between the stationary rolls and theexternal periphery of said shaft, said main movable rolls being heldagainst said rotary shaft and said stationary rolls by said spring meansand being rotatably supported in said positions, whereby a predeterminedtorque between said shaft and said clutch member forces said mainmovable rolls against said rotary shaft and said stationary rolls forclutching said shaft and clutch member together, and a torque largerthan said predetermined torque forces said main movable rollers pastsaid stationary rolls and said shaft runs freely within said mainmovable rolls. 7

2. A torque clutch as claimed in claim 1 further comprising clutchoperation auxiliary rolls rotatably positioned between said annularclutch member and said rotary shaft and between adjacent main movablerolls for stabilizing clutch action.

3. A torque clutch as claimed in claim 1 in which said stationary rollsare resilient rolls and said clutch member has recesses in the internalperiphery thereof in which said resilient rolls are mounted.

4. A torque clutch as claimed in claim 1 in which the internal peripheryof said clutch member has a plurality of projections thereon definingbetween them grooves in which said stationary rolls are positioned, apin on each projection, and said spring members each comprise a twistedcoil spring having a coil portion mounted on said pin and having legsdepending toward the shaft from the coil portion and engaged with themain movable rolls for urging them into contact with the stationaryrolls and said shaft.

1. A torque clutch for an air wrench, comprising an annular clutchmember, a rotary shaft positioned within said annular clutch member witha space between the annular shaft and the clutch member, a plurality ofstationary rolls mounted at intervals around the internal periphery ofsaid annular clutch member, a plurality of spring members mounted aroundthe internal periphery of said annular clutch member at positionsadjacent said stationary rolls, a plurality of main movable rolls equalin number to the number of stationary rolls and having a diameterslightly larger than the clearance between the stationary rolls and theexternal periphery of said shaft, said main movable rolls being heldagainst said rotary shaft and said stationary rolls by said spring meansand being rotatably supported in said positions, whereby a predeterminedtorque between said shaft and said clutch member forces said mainmovable rolls against said rotary shaft and said stationary rolls forclutching said shaft and clutch member together, and a torque largerthan said predetermined torque forces said main movable rollers pastsaid stationary rolls and said shaft runs freely within said mainmovable rolls.
 2. A torque clutch as claimed in claim 1 furthercomprising clutch operation auxiliary rolls rotatably positioned betweensaid annular clutch member and said rotary shaft and between adjacentmain movable rolls for stabilizing clutch action.
 3. A torque clutch asclaimed in claim 1 in which said stationary rolls are resilient rollsand said clutch member has recesses in the internal periphery thereof inwhich said resilient rolls are mounted.
 4. A torque clutch as claimed inclaim 1 in which the internal periphery of said clutch member has aplurality of projections thereon defining between them grooves in whichsaid stationary rolls are positioned, a pin on each projection, and saidspring members each comprise a twisted coil spring having a coil portionmounted on said pin and having legs depending toward the shaft from thecoil portion and engaged with the main movable rolls for urging theminto contact with the stationary rolls and said shaft.